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A145279 Fecundity of Fibonacci numbers 1
0, 10, 10, 9, 9, 1, 7, 7, 5, 2, 1, 3, 1, 5, 8, 0, 5, 2, 1, 3, 1, 0, 1, 1, 7, 0, 2, 3, 3, 5, 0, 1, 0, 5, 0, 1, 0, 5, 0, 1, 0, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 2, 1, 3, 5, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Subset of A070562. After the 184th Fibonacci number 127127879743834334146972278486287885163 the fecundity is equal to zero.

The indices of Fibonacci numbers whose fecundity are not zero are: {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 22, 23, 24, 26, 27, 28, 29, 31, 33, 35, 37, 39, 42, 43, 53, 54, 55, 56, 57, 58, 78, 80, 85, 87, 97, 125, 184}. [From Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 27 2010]

EXAMPLE

Fib(6)=8 -> 8+8=16 -> 16+1*6=22 -> 22+2*2=26 -> 26+2*6=38 -> 38+3*8=62 -> 62+6*2=74 -> 74+7*4=102 -> 7 steps to reach a zero digit.

MAPLE

P:=proc(i) local a, b, c, d, f, g, ok, k, w, n; d:=0; f:=1; print(d); print(10); for n from 0 by 1 to i do a:=d+f; g:=f; f:=a; d:=g; b:=1; c:=0; ok:=1; while ok=1 do k:=a; w:=1; while k>0 do w:=w*(k-(trunc(k/10)*10)); k:=trunc(k/10); od; if w=0 then ok:=0; else c:=c+1; a:=a+w; fi; od; print(c); od; end: P(200);

MATHEMATICA

f[n_] := Length@ FixedPointList[ # + Times @@ IntegerDigits@# &, n] - 2; Array[f@ Fibonacci@# &, 105, 0] [From Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 27 2010]

CROSSREFS

A070562, A145280

Sequence in context: A112120 A099401 A087028 * A103708 A131722 A072803

Adjacent sequences:  A145276 A145277 A145278 * A145280 A145281 A145282

KEYWORD

easy,nonn,base

AUTHOR

Paolo P. Lava & Giorgio Balzarotti (paoloplava(AT)gmail.com), Oct 06 2008

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Last modified February 15 12:25 EST 2012. Contains 205786 sequences.